Is preoperative pancreatic juice cytology useful for determining therapeutic strategies for patients with intraductal papillary mucinous neoplasm of the pancreas?

BACKGROUND: We compared the results of preoperative pancreatic juice cytology (PJC) and final pathological diagnosis after resection in patients who underwent resection of intraductal papillary mucinous neoplasm (IPMN) of the pancreas to determine whether preoperative PJC can help determine therapeutic strategies. METHODS: Of 1130 patients who underwent surgical resection IPMN at 11 Japanese tertiary institutions, the study included 852 patients who underwent preoperative PJC guided by endoscopic retrograde cholangiopancreatography (ERCP). RESULTS: The accuracy of preoperative PJC for differentiation between cancerous and noncancerous lesions were 55% for IPMN overall; 59% for the branch duct type; 49% for the main pancreatic duct type; 53% for the mixed type, respectively. On classifying IPMN according to the diameters of the mural nodule (MN) and main pancreatic duct (MPD), the corresponding values for diagnostic performance were 40% for type 1 (MN ≥5 mm and MPD ≥ 10 mm); 46% for type 2 (MN ≥5 mm and MPD < 10 mm); 61% for type 3 (MN < 5 mm and MPD ≥ 10 mm); 72% for type 4 (MN < 5 mm and MPD < 10 mm), respectively. CONCLUSIONS: PJC in IPMN is not a recommended examination because of its low overall sensitivity and no significant difference in diagnostic performance by type, location, or subclassification. Although the sensitivity is low, the positive predictive value is high, so we suggest that pancreatic juice cytology be performed only in cases where the patient is not sure about surgery.

Objective evaluation of the resistance forces of 22-gauge EUS-FNA and fine-needle biopsy needles.

Background and Objectives: EUS-guided tissue acquisition is routinely performed for the diagnosis of gastrointestinal tract and adjacent organ lesions. Recently, various types of needles have been developed. However, how the shape of the needle tip and echoendoscope tip angle affect puncturability, has not been clarified. The aim of this experimental study was to compare the puncturability of several 22-gauge EUS-FNA and EUS-guided fine-needle biopsy (EUS-FNB) needles, and to evaluate the effects of the needle tip shape and echoendoscope tip angle on tissue puncturability. Materials and Methods: The following six major FNA and FNB needles were evaluated: SonoTip® ProControl, EZ Shot 3 Plus, Expect™ Standard Handle, SonoTip® TopGain, Acquire™, and SharkCore™. The mean maximum resistance force against needle advancement was evaluated and compared under several conditions using an echoendoscope. Results: The mean maximum resistance force of the needle alone was higher for the FNB needles than for the FNA needles. The mean maximum resistance force of the needle in the echoendoscope with free angle demonstrated that the resistance forces were between 2.10 and 2.34 Newton (N). The mean maximum resistance force increased upon increases in angle of the tip of echoendoscope, particularly in the FNA needles. Among the FNB needles, SharkCore™ had the lowest resistance force (2.23 N). The mean maximum resistance force of the needle alone, the needle in the echoendoscope with free angle, and the needle in the echoendoscope with full-up angle for SonoTip® TopGain were all similar to that of Acquire™. Conclusion: SonoTip® TopGain had similar puncturability to Acquire™ in all tested situations. Regarding the puncturability, SharkCore™ is most suitable for insertion into target lesions, when tight echoendoscope tip angle is necessary.

High-intensity focused ultrasound therapy for pancreatic cancer.

Pancreatic cancer (PC) has one of the poorest prognoses among solid cancers, and its incidence has increased recently. Satisfactory outcomes are not achieved with current therapies; thus, novel treatments are urgently needed. High-intensity focused ultrasound (HIFU) is a novel therapy for ablating tissue from the outside of the body by focusing ultrasonic waves from multiple sources on the tumor. In this therapy, only the focal area is heated to 80-100 ºC, which causes coagulative necrosis of the tissue, with hardly any impact on the tissue outside the focal area. Although HIFU is a minimally invasive treatment and is expected to be useful, it is not yet generally known. Here, we discuss the usefulness of HIFU treatment for un-resectable advanced PC using the results of previous research, meta-analyses, and systematic reviews on its efficacy and safety. HIFU therapy for un-resectable PC is useful for its anti-tumor effect and pain relief, and is expected to prolong survival time and improve quality of life. Although HIFU for PC has several limitations and further study is needed, this technique can be safely performed on un-resectable advanced PC. In future, HIFU could be utilized as a minimally invasive treatment strategy for PC patients with a poor prognosis.

Novel Therapeutic Method for Unresectable Pancreatic Cancer-The Impact of the Long-Term Research in Therapeutic Effect of High-Intensity Focused Ultrasound (HIFU) Therapy.

High-intensity focused ultrasound (HIFU) is a novel advanced therapy for unresectable pancreatic cancer (PC). HIFU therapy with chemotherapy is being promoted as a novel method to control local advancement by tumor ablation. We evaluated the therapeutic effects of HIFU therapy in locally advanced and metastatic PC. PC patients were treated with HIFU as an optional local therapy and systemic chemotherapy. The FEP-BY02 (Yuande Bio-Medical Engineering) HIFU device was used under ultrasound guidance. Of 176 PC patients, 89 cases were Stage III and 87 were Stage IV. The rate of complete tumor ablation was 90.3%, while that of symptom relief was 66.7%. The effectiveness on the primary lesions were as follows: complete response (CR): n = 0, partial response (PR): n = 21, stable disease (SD): n = 106, and progressive disease (PD): n = 49; the primary disease control rate was 72.2%. Eight patients underwent surgery. The median survival time (MST) after diagnosis for HIFU with chemotherapy compared to chemotherapy alone (100 patients in our hospital) was 648 vs. 288 days (p < 0.001). Compared with chemotherapy alone, the combination of HIFU therapy and chemotherapy demonstrated significant prolongation of prognosis. This study suggests that HIFU therapy has the potential to be a novel combination therapy for unresectable PC.

EUS-guided hepaticoenterostomy with using a dedicated plastic stent for the benign pancreaticobiliary diseases: A single-center study of a large case series.

BACKGROUND AND OBJECTIVES: EUS-guided biliary drainage (EUS-BD) has recently been used for the treatment of not only malignant pancreaticobiliary diseases, but also for benign diseases. In most previous studies, EUS-BD was performed using a fully covered self-expandable metallic stent (SEMS), and data focusing on the usability of plastic stents for benign diseases are limited. We previously developed a plastic stent dedicated to EUS-guided hepaticoenterostomy (EUS-HES), and achieved favorable results in a feasibility study, although most of the patients had malignant diseases. Therefore, the aim of the present study was to evaluate the usability of dedicated plastic stents for EUS-HES in patients with benign pancreaticobiliary diseases. PATIENTS AND METHODS: A total of 57 consecutive patients (28 men, median age: 68 years; range: 7-90 years) of normal and surgically altered anatomy with benign pancreaticobiliary diseases who underwent EUS-HES using the dedicated plastic stent between Jan. 2015 and Jun. 2020 were retrospectively analyzed. Results: The overall technical success rate of EUS-HES was 92.9% (53/57). Among the 4 cases of technical failure of plastic stent placement, a SEMS was placed in 1; percutaneous transhepatic biliary drainage was performed in 1; EUS-HES was reperformed 1 week later in 1; and observational management was selected in 1 patient. Adverse events associated with the procedure were seen in 15.7% (9/57) of the patients, namely, biliary peritonitis in 4, bleeding in 2, cholecystitis in 2, and pneumoperitoneum in 1 patient. Except for 1 patient who required blood transfusion owing to bleeding and 1 patient with cholecystitis who required percutaneous transhepatic gallbladder drainage, the other 7 patients were treated by conservative therapy. There were no intervention-associated deaths. CONCLUSION: Our results demonstrated that for patients with benign pancreaticobiliary diseases in whom conventional ERCP was unsuccessful, EUS-HES using a dedicated plastic stent was safe and feasible.

Clinical Outcomes of Digital Cholangioscopy-Guided Procedures for the Diagnosis of Biliary Strictures and Treatment of Difficult Bile Duct Stones: A Single-Center Large Cohort Study.

Although Spy DS (SpyGlass DS Direct Visualization System) is considered to be useful for the diagnosis of bile duct strictures and the treatment of bile duct stones, there is limited data to date validating its efficacy. We hence retrospectively evaluated the clinical outcomes of the use of Spy DS in a large number of patients. A total of 183 patients who underwent Spy DS-guided procedures for indeterminate bile duct strictures (n = 93) and bile duct stones (n = 90) were analyzed retrospectively. All patients (93/93) with bile duct strictures successfully underwent visual observation, and 95.7% (89/93) of these patients successfully underwent direct biopsy. The sensitivity, specificity, and overall accuracy were 94.7%, 83.3%, and 90.3%, respectively, for visual impression; 80.9%, 100%, and 89.2%, respectively, for histopathological analysis of a direct biopsy; and 96.5%, 91.7%, and 94.6%, respectively, for visual impression combined with biopsy. Successful visualization of the stones was achieved in 98.9% (89/90) of the patients, and complete stone removal was achieved in 92.2% (83/90) of the patients, with an average of 3.3 procedures. The adverse events rate was 17.5% (32/183; cholangitis in 15 patients, fever the following day in 25, pancreatitis in 1, hemorrhage in 1, and gastrointestinal perforation in 1). No administration of antibiotics before the procedure was found to be a statistically significant risk factor for the development of fever after the procedure (p < 0.01). Spy DS-guided procedures are effective for the diagnosis and treatment of bile duct lesions and can be performed with a low risk of serious adverse events.

A case of juvenile eosinophilic cholangitis: Rapid peripheral blood hypereosinophilia after admission leading to diagnosis.

A 15-year-old boy was referred to our hospital with elevated hepatobiliary enzyme levels and jaundice. Magnetic resonance cholangiopancreatography performed at the previous medical facility revealed a stricture of the intrahepatic and extrahepatic bile duct. Computed tomography showed dilatation and wall thickness of the intrahepatic bile ducts. Primary sclerosing cholangitis or cholangiocarcinoma was suspected. Endoscopic retrograde cholangiopancreatography (ERCP) showed stricture in the intrahepatic and extrahepatic bile duct. On admission, the eosinophil count in the peripheral blood was normal; however, rapid hypereosinophilia in the peripheral blood was observed after admission, leading us to suspect eosinophilic cholangitis (EC). A bile duct biopsy showed inflammatory cells and eosinophil infiltration during a second ERCP. The patient was diagnosed with EC based on histopathology.

Novel method for evaluating the indication for endoscopic papillectomy in patients with ampullary adenocarcinoma.

This study aimed to determine the clinicopathological features of the subtypes of ampullary carcinoma (AC) to explore the indications for endoscopic papillectomy (EP) in early AC. Fifty-seven patients with AC who underwent curative resection were retrospectively reviewed. The 0/IA stages were significantly more common in the intestinal type (I-type) than in the mixed and pancreatobiliary type (M&PB-type) (90.7% vs 35.7%, P < 0.001). Tis/T1a tumors limited to the ampulla [Tis/T1a(ampulla)] were significantly more likely to be I-type than M&PB-type (74.4% vs 14.3%, P = 0.002). The tub1 rate was significantly higher in the I-type than in the M&PB-type (81.4% vs 35.7%, P = 0.001). In the I-type, the tub1 rate was significantly higher for Tis/T1a(ampulla) than for T1a tumors limited to the sphincter of Oddi (100% vs 42.9%, P = 0.004). These observations suggest that I-type AC with tub1 is an indication for EP. The concordance rate of pathological subtypes between endoscopic biopsy and resected specimens was high (κ = 0.8053, P < 0.001). Tis/T1a(ampulla) showed no lymphovascular or perineural invasion. An endoscopic imaging finding of early AC with I-type and tub1 on biopsy could be an indication for EP. Identifying the pathological subtype of AC by endoscopic biopsy could be a novel preoperative approach for evaluating the indications for EP.

Efficacy of the Franseen needle for diagnosing gastrointestinal submucosal lesions including small tumors.

BACKGROUND AND OBJECTIVES: Several studies have demonstrated that EUS-guided fine-needle biopsy (EUS-FNB) is useful for diagnosing gastrointestinal subepithelial lesions (GI SELs). However, there is limited evidence regarding the use of Franseen needles during EUS-FNB for patients with GI SELs. In addition, the optimal approach for diagnosing small SELs is unclear. This study aimed to evaluate whether EUS-FNB using a Franseen needle was effective for diagnosing GI SELs, including small lesions. METHODS: Between January 2013 and January 2020, 150 consecutive patients with GI SELs underwent EUS-FNA/FNB to achieve a histological diagnosis. Eighty-six consecutive patients who underwent EUS-FNB using a Franseen needle were compared to 64 patients who underwent EUS-FNA using a conventional needle. RESULTS: The diagnostic yield was significantly higher using a Franseen needle than using a conventional needle (85% vs. 75%, P = 0.006). Furthermore, in cases with SELs that were <20 mm, the diagnostic yield was significantly higher using a Franseen needle than using a conventional needle (81% vs. 45%; P = 0.003). Multivariate analysis revealed that obtaining a sufficient diagnostic sample was independently predicted by Franseen needle use (adjusted odds ratio: 2.8, 95% confidence interval: 1.2-6.3; P = 0.01) and tumor size of >20 mm (adjusted odds ratio: 3.4, 95% confidence interval: 1.4-8.2; P = 0.006). CONCLUSION: Even when attempting to diagnose small GI SELs, EUS-FNB using a Franseen needle appears to provide a more efficient acquisition of true histological core tissue than using a conventional needle.

Pre-aspiration of a large retention cyst followed by EUS-FNB for the successful diagnosis of a patient with pancreatic cancer.

Endoscopic ultrasonography-guided fine needle biopsy is an indispensable tool for the diagnosis of pancreatic tumors but is occasionally difficult to perform owing to cystic lesions that intervene with the puncture route. Yamamoto and colleagues recommend a pre-aspiration technique in patients with pancreatic cancer and a retention cyst in the puncture route.

Three Cases of Ampullary Neuroendocrine Tumor Treated by Endoscopic Papillectomy: A Case Report and Literature Review.

We herein report three cases of patients with an ampullary neuroendocrine tumor (NET), who underwent endoscopic papillectomy (EP). No tumor recurrence or metastasis was detected in the patients for more than two years after EP. Generally, surgical resection is recommended for ampullary NETs by the European Neuroendocrine Tumor Society. However, as EP is less invasive than surgical resection, there are some reports of low-grade small ampullary NETs curatively treated by EP with long-term follow-up. We consider that EP may be a curative treatment for small and low-grade ampullary NETs without regional or distant metastasis.

Clinical Impact of Piecemeal Resection Concerning the Lateral Spread of Ampullary Adenomas.

Objective Endoscopic papillectomy (EP) has been recognized to be a safe and reliable treatment modality for ampullary adenomas. The purpose of this study was to determine the safety and efficacy of endoscopic piecemeal resection for laterally spreading ampullary adenomas and to compare these findings with a control population of smaller conventional ampullary tumors treated in the same time period. Methods Between May 1999 and September 2015, 136 patients underwent EP at Tokyo Medical University hospital. A total of 125 patients underwent en bloc resection, and 11 patients underwent piecemeal resection. Results The final pathological diagnoses were 103 adenomas, 14 carcinomas in adenomas, 4 carcinomas, and 4 hyperplasia in the en bloc resection group, versus 7 adenomas, 3 carcinomas in adenoma, and 1 carcinomas in the piecemeal resection group. A single treatment session was possible in 104 (83.2%) of the 125 patients in the en bloc resection group and in 8 (72.7%) of the 11 in the piecemeal resection group. The total resection rate including additional treatments was 98.4% in the en bloc resection group and 100% in the piecemeal resection group. Conclusion Piecemeal resection for laterally spreading ampullary adenomas was sufficiently performed compared with en bloc resection.

A retrospective histological comparison of EUS-guided fine-needle biopsy using a novel franseen needle and a conventional end-cut type needle.

BACKGROUND AND OBJECTIVES: Recently, a 22G Franseen needle for EUS-guided fine-needle biopsy (EUS-FNB) with three novel symmetric heels has been developed to adequately obtain a core tissue. METHODS: All 38 consecutive patients with pancreatic masses who underwent EUS-FNB using a Franseen needle were investigated retrospectively to assess the efficacy and safety of EUS-FNB using the Franseen needle. Then, the EUS-FNB outcomes and histological assessments of the tissue obtained by EUS-FNB using the Franseen needle and EUS-FNA using the conventional end-cut type needle for each of the 30 pancreatic ductal adenocarcinoma cases were compared. RESULTS: An accurate histological diagnosis of the Franseen needle was achieved with a mean of 2 passes in 97.4% of patients. Although the accurate histological diagnosis rate of pancreatic ductal adenocarcinoma was not significantly different (96.7% vs. 93.3%, P = 0.55), the mean number of passes in the Franseen needle was significantly less than that in the conventional needle (2.1 ± 0.4 vs. 3.2 ± 0.8, P < 0.001). The presence of desmoplastic fibrosis with neoplastic cellular elements and venous invasion were significantly higher (96.7% vs. 40.0%, P < 0.001 and 23.3% vs. 0%, P < 0.01, respectively) and the amount of obtained tissue was significantly larger with the Franseen needle (2.13 mm2 vs. 0.45 mm2, P < 0.001). CONCLUSIONS: EUS-FNB using the Franseen needle enables the acquisition of a larger amount of tissue sample and achieves an accurate histological diagnosis with a smaller number of passes than the conventional end-cut type needle.

Expanding the indication of endoscopic papillectomy for T1a ampullary carcinoma.

BACKGROUND AND AIM: Endoscopic papillectomy (EP) has been attempted not only for benign lesions but also for early ampullary carcinoma (AC). However, there is still no sufficient evidence or consensus regarding the effectiveness of EP for early AC. Herein, we evaluated the expanding indication of EP for early AC. METHODS: Between May 1999 and December 2016, 177 patients were diagnosed with ampullary tumor before undergoing EP, and their clinical and histopathological data were analyzed retrospectively. RESULTS: There were 27 Tis-T1a AC patients and four T1b AC patients who underwent EP. Mean tumor size was 14.1 mm for Tis-T1a AC and 17.0 mm for T1b AC. For the histological grade, 50% (2/4) of T1b AC were moderately differentiated, whereas 96.3% (26/27) of Tis-T1a AC were well differentiated and papillary. For lymphovascular invasion, one (25%) occurred in T1b AC but none occurred in Tis-T1a AC. There was no AC recurrence from the date of EP until a maximum of 5 years (Tis-T1a: mean period 48.5 months [5-60]; T1b: mean period 26.5 months [3-60]). CONCLUSIONS: Endoscopic papillectomy is useful and reliable for the curative treatment of T1a AC. Large-scale prospective studies with long-term follow up are needed.

EUS-guided antegrade metal stenting with hepaticoenterostomy using a dedicated plastic stent with a review of the literature (with video).

BACKGROUND AND OBJECTIVES: Recently, a novel EUS-guided biliary drainage (EUS-BD) technique consisting of EUS-guided antegrade stenting and EUS-guided hepaticoenterostomy (EUS-AS+HES) using two conventional metal stents (MS) has been reported to decrease adverse events and maintain longer stent patency for malignant biliary obstruction (MBO). However, only a few limited reports have evaluated this technique. Finally, dedicated plastic stents (PSs) have been developed to perform EUS-HES safely. The aim of the present study was to evaluate the outcome in EUS-AS+HES for MBO using the dedicated HES PSs. METHODS: The results of a total of 23 patients who underwent EUS-AS+HES (18 simultaneous cases and 5 sequential cases) for MBO from October 2014 to July 2017 were retrospectively reviewed. RESULTS: Technical and clinical success rates were 100% (23/23). Adverse events were seen in 8.7% (2/23); 2 cases of mild biliary peritonitis, which were successfully managed conservatively. Overall survival was 96 days and the median duration of stent patency, including stent dysfunction, patient death, and last follow-up, was 66.0 days (53 days in simultaneous cases and 78 days in sequential cases). Stent dysfunction was seen in 13.0% (3/23) of patients in 267, 263, and 135 days after the procedure. CONCLUSIONS: The novel EUS-BD technique, EUS-AS using MS plus HES employing a dedicated PS, was shown to be a feasible procedure for MBO and should yield longer duration of stent patency. Furthermore, sequential antegrade stenting in cases of occluded HES seems to be one other option instead of HES stent exchange. Further large-scale comparison studies with EUS-HES or EUS-AS are required to confirm its clinical efficacy.

Evaluation of a new stent for EUS-guided pancreatic duct drainage: long-term follow-up outcome.

BACKGROUND AND STUDY AIMS: Endoscopic ultrasonography-guided pancreatic duct drainage (EUS-PD) has been reported as an alternative for failed conventional endoscopic retrograde cholangiopancreatography (ERCP). However, there are few dedicated devices for EUS-PD. Recently, we have developed a new plastic stent dedicated to EUS-PD and have conducted a feasibility study to evaluate its efficacy. In the current study, we evaluated the long-term efficacy of this new plastic stent. PATIENTS AND METHODS: Thirty patients (61 ±â€Š14.3 years old, 14 men) with acute recurrent pancreatitis caused by a stricture in the main pancreatic duct (MPD) or stenotic pancreatoenterostomy were treated at our institution using our recently developed 7Fr plastic stent between August 2013 and April 2017. RESULTS: The stent was placed successfully in all patients (30/30) and early clinical success was achieved in all of them. Early adverse events (AEs) occurred in seven patients (23.3 %), namely, self-limited abdominal pain (n = 5), mild pancreatitis (n = 1), and bleeding which required transcatheter arterial embolization (n = 1). Two patients died of primary disease and three were lost to follow-up. The remaining 25 patients were followed up after initial EUS-PD for a median of 23 months (range, 6 - 44 months). Twenty patients required regular stent exchange (3 times; range, 1 - 12 times). Spontaneous stent dislodgement was observed in six patients. Four patients wanted their stents removed 1 year after the initial intervention. Twelve patients (48 %) had regular stent exchange 1 year after the initial intervention. Three patients converted to standard transpapillary pancreatic duct stenting by conventional ERCP. Finally, nine patients (36 %) had complete stent removal either intentionally or by spontaneous dislodgement without any symptoms. CONCLUSION: The new plastic stent for EUS-PD was associated with not only short-term technical success but also long-term clinical success in the majority of patients evaluated in this study.

Elevated Polyamines in Saliva of Pancreatic Cancer.

Detection of pancreatic cancer (PC) at a resectable stage is still difficult because of the lack of accurate detection tests. The development of accurate biomarkers in low or non-invasive biofluids is essential to enable frequent tests, which would help increase the opportunity of PC detection in early stages. Polyamines have been reported as possible biomarkers in urine and saliva samples in various cancers. Here, we analyzed salivary metabolites, including polyamines, using capillary electrophoresis-mass spectrometry. Salivary samples were collected from patients with PC (n = 39), those with chronic pancreatitis (CP, n = 14), and controls (C, n = 26). Polyamines, such as spermine, N1-acetylspermidine, and N1-acetylspermine, showed a significant difference between patients with PC and those with C, and the combination of four metabolites including N1-acetylspermidine showed high accuracy in discriminating PC from the other two groups. These data show the potential of saliva as a source for tests screening for PC.

The Role of Endoscopic Ultrasound-guided Drainage for Autoimmune Pancreatitis-associated Pancreatic Cysts: A Report of Five Cases and a Literature Review.

Objective Autoimmune pancreatitis (AIP) has been recognized as a benign disease, which that shows a prompt response to corticosteroid treatment (CST). It was previously believed to not be associated with cyst formation; however, a few cases of AIP-associated pancreatic cyst (PC) have been reported. Some cases were reported to have been effectively treated by CST, while others were refractory to CST. Many of the patients received interventional treatment. Until now, there has been no consensus on the therapeutic strategies for AIP-associated PC. The aim of the present study is to describe a therapeutic strategy for this condition. Methods We conducted a retrospective study of 5 cases of AIP-associated PC that were treated by endoscopic ultrasonography-guided pancreatic fluid collection drainage (ESPD) or CST at Tokyo Medical University Hospital between March 2012 and October 2016, analyzed the therapeutic outcomes, and performed a literature review. Results The initial treatments included CST (n=2) and ESPD (n=3). All of the PCs disappeared after treatment In 1 of the patients who received CST case and 3 of the patients who received ESPD; however, the PC did not disappear in one of the patients who received CST (corticosteroid maintenance therapy), even after the dose of corticosteroids was increased; ESPD was eventually performed and the PC disappeared. There were no procedure-related complaints. Conclusion We propose that CST be administered as the first-line treatment for AIP-associated PC, particularly in cases of PC without a history of CST. However, ESPD can be applied to treat cases of corticosteroid refractory PC.

Novel ex vivo training model for freehand insertion using a double-bending peroral direct cholangioscope.

BACKGROUND AND AIM: Several experts of direct peroral videocholangioscopy (D-PVCS) using a conventional ultraslim endoscope have reported its usefulness for the diagnosis and therapy of biliary tract diseases. We have additionally developed a dedicated double-bending D-PVCS technique for freehand scope insertion. In this study, we developed an ex vivo training model for the freehand double-bending D-PVCS technique and compared it with the technique using a conventional ultraslim endoscope. METHODS: The ex vivo model was made for training using a U-shape insertion pattern. A third prototype endoscope and an ultraslim upper gastrointestinal endoscope were used. Two experts and nine non-experts performed D-PVCS using the freehand technique. RESULTS: The two experts could not advance the tip of the endoscope to the hilar portion using the freehand technique, but they could achieve technical successful insertion to the hilar portion with the third prototype cholangioscope using the freehand technique alone. The non-experts could not advance the tip of the endoscope to the bile duct using the freehand technique. On the other hand, two (22.2%) non-experts could advance the tip of the third prototype cholangioscope using the freehand technique before the training conducted by the experts. After the training, all the non-experts could advance the tip of the third prototype cholangioscope to the hilar portion. CONCLUSIONS: The novel ex vivo model using a third prototype cholangioscope was useful for training in the use of the freehand D-PVCS technique.